Skin Flashcards
Squamous vs cuboidal vs columnar shaped cells
-Squamous are wider than tall
-Cuboidal are as wide as tall like cubes
-Columnar are taller than wide like columns
Function and location of simple squamous epithelium?
Func - allows passage of materials by diffusion and filtration in sites where protection is not important - secretes lubricating substances in serosae
Location - kidney glomeruli, air sacs of lungs, lining of heart, blood vessels, lymphatic vessels, lining of ventral body cavity (serosae)
What occurs in the disease Emphysema?
-Elastin and collagen are destroyed
-Air goes into lungs but is unable to come out on its own and remains in the lung
-Causes bronchioles to collapse
-Destruction of alveolar walls and capillaries - reduced surface area for O2 diffusion
-Compensation is done by increasing respiratory rate to increase alveolar ventilation
-Hypoxemia usually develops late in disease
What is the func and loaction of simple cuboidal epithelium?
-Secretion and absorption
-Kidney tubules, ducts and secretory portions of small glands, ovary surface
Func and location of simple columnar epithelium?
-Absorption, secretion of mucus, enzymes etc, ciliated type propels mucus by ciliary action
-Nonciliated type lines most of digestive tract (stomach to anal canal), gallbladder, excretory ducts, ciliated lines small bronchi, uterine tubes, some regions of uterus
GI TRACT
Func and location of stratified squamous epithelium?
-Protects underlying tissues in areas subjected to abrasion
-Nonkeratinised- forms moist linings of esophagus, mouth, vagina, urethra, anus
-Keratinised- epidermis of skin, dry membrane
Func and loaction of stratified cuboidal epithelium?
-Protection
-Largest ducts of sweat glands, mammary glands, salivary glands
Func and location of stratified columnar epithelium?
-Protection and excretion
-Rare in body, small amounts in male urethra and in large ducts of some glands
Func and loaction of pseudostratified columnar epithelium
-Secretion, particularly of mucus, propulsion of mucus by ciliary action
-Nonciliated - in males sperm carrying ducts and ducts of large glands
-Ciliated variety lines trachea, most of upper respiratory tract
What is metaplasia?
The transformation of an epithelium into another type of epithelium
what is dysplasia?
The enlargement of a tissue by proliferation of cells of an abnormal nature
What is adenocarcinoma?
Malignant tumour formed from glandular structures in epithelial tissues
What are the 3 layers of the skin and what is the primary structure of each layer?
1) Epidermis - outer/most superficial - PS- Keratinocytes
2) Dermis - middle - PS- Connective tissue and dermal capillaries
3) Hypodermis (subcutaneous layer) - deepest layer - PS- loose connective tissue and adipose tissue
What is the Epidermis composed of and what are its major functions?
-Stratified squamous epithelium
-Multiple layers of keratine containing epithelial cells - keratinocytes w melanocytes(protection from UV), merkel cells (sense touch) and langerhans (immune func) dispersed throughout
-Maintenance of fluid and electrolyte balance
-Protection from UV light
-Sensory and immune func
What are the 4 layers in the diff stages of keratin maturation?
Stratum corneum
Stratum granulosum
Stratum spinosum
Stratum basale (closest to dermis)
What is in the stratum corneum layer of epidermis?
-Thickest layer -20-30 cells thick
-Dead cells called Corneocytes that conatin keratin
What is in the stratum granulosum of the epidermis?
-Thin layer - 3-5 keratinocytes thick
-Granules contain glycolipids - waterproofing
What is in the stratum spinosum layer of epidermis?
-Keratinocytes linked by desmosomes
-Cell contain bundles of Prekeratin
-Contain langerhans cells - (epidermal dendritic cells), type of macrophage
What is the the stratum basale of epidermis?
-Layer closest to dermis
-Stem cells and younger keratinocytes
-melanocytes (scavenge free radicals - protect againts UV) and merkel cells (tactile epithelial cells - sensory receptors- touch)
